1. Field of the Invention
The present invention relates to a susceptor for semiconductor manufacturing apparatus that secures a substrate by vacuum chucking.
2. Description of the Related Art
As disclosed in Japanese Patent Laid-Open No. 2002-184844, susceptors for semiconductor manufacturing apparatus have been known which include a support member on which a substrate is placed, a recessed wafer pocket formed on an upper surface of the support member, a seal band that supports the substrate at a periphery of the wafer pocket, and a through hole formed in the wafer pocket, and which secure the substrate onto an upper surface of the seal band by evacuation through the through hole from the upper surface of the support member toward a lower surface of the same. Such a susceptor for semiconductor manufacturing apparatus can prevent a warp or displacement of a substrate when it is machined.
According to the conventional susceptor for semiconductor manufacturing apparatus, however, pressure reduction in a space between the wafer pocket and a rear surface of the substrate hinders heat transfer from the susceptor to the substrate in a wafer pocket area, so that the temperature of a substrate region above the wafer pocket becomes comparatively low. In contrast, the seal band, which is in direct contact with the substrate, transfers a large amount of heat from the susceptor to the substrate, so that the temperature of a substrate region above the seal band becomes comparatively high. Therefore, this conventional susceptor for semiconductor manufacturing apparatus produces a heat-distributed condition in an in-plane direction of the substrate when vacuum chucking is being done, which makes the thermal uniformity of the substrate worse.
The present invention has been made to solve the aforementioned problem, and an object thereof is to provide a susceptor for semiconductor manufacturing apparatus which exhibits excellent thermal uniformity of a substrate even when vacuum chucking is being done for the substrate.